The present invention relates to a system and a method for selectively applying a coating material onto a surface, and deals more particularly with a system providing a means for applying a dielectric material to surfaces situated adjacent to or on live, high voltage electrical terminals and bus work.
As is generally known, electrical power distribution systems utilize transformers which step up power to distribute it down line from the power source and subsequently utilize transformers to step down this power into usable voltage distributed to local communities and/or industries. These transformers generally provide three-phase power, with each transformer having a plurality of terminals extending outwardly, usually upwardly, from the body of the transformer to connect it with input and output lines. Each transformer is designed to have sufficient spacing between these terminals and between such terminals and ground source, to avoid what is commonly known as flashovers between differently phased terminals or between a single terminal and a source of ground potential. However, flashovers nevertheless sometimes unintentionally occur particularly when a small animal such as a squirrel leaps from one terminal to another or between a terminal and a source of ground. The flashover problem is substantially peculiar to transformers receiving input voltages ranging approximately between 14 kilovolts and 47 kilovolts. Flashovers in transformers receiving input voltages greater than 47 kilovolts do not occur very often since small animals seem to avoid such transformers, perhaps because of the strong electromagnetic flux generated around the transformer area by the increased voltage.
When a small animal creates a flashover in a transformer it becomes a conductor creating a short circuit usually causing the transformer to burn out. Loss of power to the area serviced by the transformer then occurs. Businesses effected are damaged by downtime or product spoilage, as in the case of a business selling refrigerated goods. In addition to these foreseeable damages, a further, more direct one is incurred when the transformer is replaced at a cost usually of millions of dollars. Moreover, replacement of the burnt-out transformer requires the utility company to switch and divert power to other transformers not normally servicing the area. Downtime for a single transformer not in use has been determined in some cases to cost a utility company approximately $7,000 per minute.
Different solutions have been tried to remedy the flashover problem in transformers. Fences have been erected around transformers but do not effectively enclose the transformers from animals since openings must be provided to allow access to the overhead lines. Another solution would be to manually insulate the terminal surfaces by utilizing workers who would cover the affected surfaces with insulation. Clearly, it is dangerous for workers to get close to live high voltage terminals since they are likely to be electrocuted. Thus, the transformers would have to be shut down in order that the workers be allowed to insulate. The cost, however, incurred by a utility company in disconnecting power to each transformer and subsequently insulating areas on each transformer affected by flashover is prohibitive. Thus, flashover problems in transformers must be remedied by a system which services live transformers while preserving worker safety.
Accordingly, in the present invention, it is an object of the invention to provide a system which applies a dielectric coating material to surfaces situated adjacent to or on high voltage electrical terminals and bus work when the transformer is live and which coating covers and insulates these surfaces thus preventing the problem of flashover occurring between these surfaces.
Another object of the present invention is to provide an electrically insulated mobile application system having adjustable components which are capable of being assembled to correspond in height and dimension with differently sized transformers.
Yet a further object of the invention is to provide a system isolating liquified coating material being pumped to live transformer terminals, bus work or to a transformer top surface from potential ground or electrical sources.
Yet a further object of the present invention is to provide a system having numerous electrical isolation redundancies which insure system safety by a factor of at least two.